Promo: order page + red banner + contact form; fix admin login rehash

- /order page: single tag $5.50 / 10-pack $22.00 (GST-incl), qty via
  Stripe Payment Links (single 1-25, pack 1-2), thanks state
- Red 'Protect & recover your valuables — ORDER NOW' banner in base layout
  (every page incl. found-dog tag page) + footer promo links
- Contact page: form -> Gmail SMTP (env SMTP_*), hello@where-woof.com
- Fix admin login 500: User.getAuthPasswordName() = password_hash so
  Laravel 13 rehash-on-login writes the correct column (was trying
  UPDATE users SET password = ...)

frontend/internal/handlers/pages.go

@@ -14,5 +14,11 @@ func (a *App) WhatIsThis(w http.ResponseWriter, r *http.Request) {
 
 // Contact renders the contact page.
 func (a *App) Contact(w http.ResponseWriter, r *http.Request) {
-	a.render(w, r, "contact", "Contact", nil, "")
+	a.render(w, r, "contact", "Contact", contactData{}, "")
 }
+
+// contactData passed to the contact page (form submission state).
+type contactData struct {
+	Sent  bool
+	Error string
+}